Figure 4
Thickness and line width at various biases. Height/bias dependence for oxide lines (a) and carbonaceous lines (b). AFM topographies and profiles refer to features written at 1 μm s−1. (c to f) Height/bias relation plotted for different Si surfaces, Si:OH or pristine (with native oxide layer), H-terminated, and methyl-terminated; for positive tip bias (carbonaceous), we show the Si(H) surface. Black marks refer to height, and red marks refer to the line width expressed as FWHM. The smallest lateral resolution (<40 nm) is achieved for oxide features on Si(H); similar line width is observed for Si(CH3), while as the surface becomes more hydrophilic, line width raises above 100 nm (d). As expected, oxide height (c to e) increases linearly with bias for all surfaces in the 5- to 11-V interval with a similar height/bias dependence. With a negative sample bias, the deposition still depends on voltage (f).